1. Field of the Invention
The present invention relates to an ultrasonic cleaning method and device. More particularly, the present invention relates to an ultrasonic cleaning method and device suitably used for a process in which it is necessary to clean a mechanically machined part in the shortest period of time.
2. Description of the Related Art
In the case of machining a product, it is necessary to conduct cleaning to remove foreign objects such as chips and to remove oil and fat used for supporting a machining process. This cleaning is needed not only for manufacturing a machined product but also for manufacturing an electric appliance. An ultrasonic cleaning method of cleaning an object to be cleaned, which is put in water or solvent, by utilizing ultrasonic waves of high frequencies is widely used in the industrial field. The ultrasonic cleaning method described above is especially suitable for cleaning an object, the shape of which is so complicated that it is difficult to conduct cleaning by a method in which fluid is jetted onto the object to be cleaned. The ultrasonic cleaning method described above is also suitable for cleaning a fragile object. Even in the field to which ultrasonic cleaning method is suitably applied, as a product may be accurate and complicated, it may be required to conduct highly accurate and more complete cleaning. As a result, it may be required to conduct more effective cleaning.
According to the conventional ultrasonic cleaning method, in order to enhance a cleaning force (ability) with respect to an object to be cleaned, the number of oscillators, which are attached to a unit area of an oscillation plate, is increased, and an input of electric power into an ultrasonic oscillator is increased, so as to enhance an ultrasonic force (a cleaning force) produced by the ultrasonic oscillation plate. However, according to this method, an excessively heavy load is given to the ultrasonic oscillator and the ultrasonic oscillation plate. Accordingly, these components are likely to be damaged and abraded in a short period of time. Even when deaerated liquid is utilized, the liquid temperature is controlled at an appropriate temperature and the most appropriate cleaning solution is selected for removing contamination, in order to obtain an ultrasonic force of the maximum intensity, a problem that an excessively heavy load is required to be applied to the ultrasonic generator for controlling the oscillation of ultrasonic waves occurs. Due to the physical limits described above, it was difficult to conduct a high speed cleaning operation by increasing an ultrasonic force (a cleaning force) in the prior art.